1. Field of the Invention
The present invention relates to an instant camera. More particularly, the present invention relates to an instant camera capable of spreading processing solution in each photo film unit in a stably controlled manner.
2. Description Related to the Prior Art
A widely available instant camera is used with a photo film pack, which includes plural photo film units of a self-processing type. Each of the photo film units has an exposure surface, and a processing solution pod disposed on one edge of the exposure surface. The solution pod contains processing solution. The photo film pack has a case of a box shape, which encloses the photo film units light-tightly to be sold as a product. When the instant camera is loaded with the photo film pack, it is possible to take photographs without handling each of the photo film units individually.
When an exposure is taken in an instant camera on the exposure surface of the photo film unit with light from a photographic subject, the camera causes the photo film unit being exposed to moved to the outside. In the course of this exiting movement, a pair of spreader rollers nip and squeeze the solution pod, and causes the processing solution to flow from the solution pod to the exposure surface, to develop the exposure surface.
There are various ways conceivable for improving the quality of a printed image on the photo film unit in the instant camera. Among them, JP-B 3-72975 (corresponding to U.S. Pat. No. 4,226,519) suggests spreading of the processing solution to the exposure surface in a uniform manner. A spread control surface is formed with the photo film outlet in the case to contact the exposure surface in the photo film unit. When the processing solution flows from the solution pod, the spread control surface spreads the processing solution on the exposure surface before the spreader rollers spreads the processing solution. Thus the spread control surface causes the processing solution to extend to lateral portions arranged in the film unit width direction, which would be impossible if the spread control surface were not added to the spreader rollers. According to this prior art, the quality of the printed image can be heightened. Also the cost of the photo film unit can be reduced by optimizing the amount of the processing solution as contained.
To stabilize the effect of the spread control surface controlling the spread of the processing solution, it is necessary to regularize a contacting position, contacting pressure, and other contacting states between the spreader rollers and the spread control surface. The case of the photo film pack consists of a combination of plural parts formed from plastic material with a small thickness, and is likely to be deformed due to irregularities in the size occurring at the molding time or assembly time, and twisting or distortion in the shape according to temperature or the like. A problem lies in that a relative position between the spread control surface with the spreader rollers is likely to change, so as to change the control of spreading the processing solution.